Micrometer 400

GaugeCollection.java

package io.micrometer.core.samples;

import io.micrometer.core.instrument.MeterRegistry;
import io.micrometer.core.instrument.Tags;
import io.micrometer.core.samples.utils.SampleConfig;

import java.util.Collections;
import java.util.List;

public class GaugeCollection {
    public static void main(String[] args) throws InterruptedException {
        MeterRegistry registry = SampleConfig.myMonitoringSystem();

        List<Integer> someList = Collections.singletonList(1);

        registry.gaugeCollectionSize(
                "gauge.list",
                Tags.of("sometag", "tag.value"),
                someList);

        for(int i = 0; i < 20; i++) {
            Thread.sleep(1000);
        }

        System.out.println("made list null");
        someList = null;

        // at some point, the list gets garbage collected and the metric drops off of Datadog
        for(;;) {
            Thread.sleep(100);
        }
    }
}